Key Provisioning is a common problem to almost all cryptographic modules. Whenever a cryptographic device is designed to carry out operations using internally-stored key material, this key material needs to be available to the device.
For most key material, provisioning is done by means defined at the application level. Most applications support methods to securely communicate keys to the participants of their security protocols. Provisioning methods specified by applications usually rely on pre-existing key material, which is used to secure the subsequent provisioning process. Other applications carry out provisioning without pre-existing key material, if their threat models allow that.
Key Provisioning remains an open problem for initial key material that is inserted into devices. Such a provisioning process cannot rely on pre-existing key material, because there is none. It is also often too sensitive to rely on unencrypted key delivery, even if the device is assumed to still be within secure premises.
Moreover, it is often the case that the entity that happens to install the key material in a device (hereafter referred to as Installer), while operating on behalf of the owner of the device asset (hereafter referred to as Owner), is not entirely trusted by Owner. The provisioning process, if carried out without measures against compromise by Installer, requires extremely high levels of trust on behalf of Owner. In many cases, such trust cannot be granted, leading to the need to devise a system that protects the provisioning process against compromise also by Installer.
Another source for complexity stems from the existence of Sub-owners. A Sub-owner is an entity which is not the owner of the device asset, but which owns some of the key material to be placed in it. Each Sub-owner has its own Installer (one or more). The same trust issue between the Owner and its Installer for each Sub-owner or any of its respective Installers. Another situation partial distrust occurs between the Owner or its Sub-owners. The Owner of the Sub-owner provide its devices with key material, but may not trust it to overwrite other key material, such as that installed by Owner or by any other Sub-owner. In most cases, Owner will not accept the ability of one of its Sub-owners to obtain key material provisioned by another Sub-owner.
The problem of key provisioning can thus be stated as the need to: (1) allow Owner allow Installer (one or more) to provide the device with key material on behalf of the Owner, without exposing the key material to the Installer performs the physical provisioning operation;                allow a similar model for more than one Sub-owner, each having associated with it one or more Installers;                    prevent any Owner from obtaining key material provisioned by another Sub-owner; and            allow Owner to control what key material each Sub-ownerprovision through its Installers, while not having possession of the key material itself.                        
The client-side of the implemented solution for the problem above shall fit within the capabilities of an embedded chip-set, and shall be made to be carried out in short times, e.g., during fabrication.